Device for obtaining predetermined speed.



W. W. DEAN.

DEVICE FOR OBTAINING PREDETERMINED SPEED.

APPLICATION FiLED JULY 6.1917.

Patented Nov. 26, 1918..

2 SHEETSSHEET I.

(1110: me Q W- W. DEAN.

DEVICE FOR OBTAINING PREDETERMINED SPEED.

APPLICATION FILED JULY 6.1917.

1,285,6%0. .Patented Nov. 26, 1918.

2 SHEETS-SHEET 2.

' '1 w gwpr i UNITED STATES PATENT OFFICE.

WILLIAM WARREN DEAN, F STAMFORD; CONNECTICUT, ASSIGNOR TO SPLITDORF ELECTRICAL COMPANY, OF NEWARK, NEW JERSEY, A CORPORATION OF NEW JERSEY.

DEVICE FOR OBTAINING PREDETERMINED SPEED.

Patented Nov. 26, 1918.

Application filed July 6, 1917. Serial No. 179,068.

To all whom it may concern.-

Be it known that I, WILLIAM W. DEAN,

- a citizen of the United States, residing at t which the following is a specification, reference being had to the accompanying drawin The invention relates'to new and useful improvements in devices for obtaining a predetermined speed and more particularly to a device for obtaining the proper speed of a phonograph record] In my co-pending application, Serial No. 179,062, filed of even date herewith, I have described and claimed broadly an apparatus or device for obtaining a predetermined speed in a driven member wherein sound 15 roduced by a mathematically divided memher which member is driven by and in synchronism with the member in which it is desired to obtain a predetermined speed and the sound so produced is compared with the tone of a pitch pipe or tuning fork and thus the speed may be regulated and a predetermined speed obtained.

An object of the invention is to provide a device of the above'character which shall be of few parts whereby the same may be cheaply made and without sacrificing the efliciency or durability thereof.

In the drawings,

Figure 1 is a view partly in section and partly diagrammatic, showing my improved device as applied to a phonograph for obtaininga predetermined speed therein;

Fig. 2 is a top plan view of the device, on an enlarged scale;

Fig. 3 is a bottom plan view of the upper or stationary member of the device;

Fig. 4 is a perspective view of the supporting bracket and one of the vibrating members and the spring for controlling the same, said parts being separated;

Fig. 5 is an enlarged sectional view on the line 5-5 of Fig. 4;

Fig. 6 is a front view of one of the lugs for supporting the spring;

Fig. 7 is a sectional view on the line 7-7 of Fig. 6;

Fig. 8 is a detail showing the vibrating device and in dotted lines the movement of the same; and I Fig. 9 is an enlarged view in top plan of a section of the lower member.

In the drawings, I have shown a phonograph table 1, which is mounted on a suitable support 2 and which is rotated by the usual mechanism. Means is also provided for adjusting the speed of said table. At 3 I have shown the reproducer of the phonograph. Extending upwardly from the table 1 is a centering pin 4. These parts are of the usual construction and further description thereof is not thought necessary.

My improved device for obtaining a predetermined speed in a rotating or driven member 1, consists of a rotatable disk or member 5, and a fixed disk 6. The disk 5 has a central opening therein which is adapted to receive the centering pin 4. On the lower faceof the disk is a felt pad 7 which protects the phonograph table and causes the disk 5 to rotate in synchronism with the table. The stationary member 6 has a depending flange 8 which is spaced from the lower disk so that said lower disk may rotate freely while the upper member 6' is held from rotation. The upper member is held from rotation by a hand piece 9 which is formed with a knurl at its outer edge adapted to be grasped by the operator so that the member 6 may be. held from rotation. The upper member 6 has a central opening therethrough and the hand piece 9 is formed with a sleeve 10 adapted to extend through-said opening in the mem-- her 6. Said hand piece has a shoulder 11 adapted to engage the upper face of the member 6. Said upper member 6 is preferably made of metal and is formed with diametrically opposed notches 12 extend ng outwardly from the central opening therein.

A sheet metal bracket 13 is provided with an opening 14 which is adapted to receive the sleeve 10 and a threaded nut 14 engaging this sleeve clamps the bracket and the member or disk 6 together and to the hand piece 9. The bracket is formed with bent up sections 1515 which are adapted to engage the notches 1212.

The rotatable disk 5 is formed at its outer edge with two rows of serrations or teeth 16 and 17. These rows of serrations are concentric with the axis of rotation of the disk 5. Cooperating with the outer row of serrations is a vibrating device 18 and co operating with the inner row of serrations is a vibrating device 19. Each vibrating device is formed with a downwardly projecting part 20 which is struck up from the metal. Each vibrating device is also provided with laterally extending pintles 21 and the bracket 13 has spaced projecting arms 2222 at one end thereof which are curved to form bearings for the pintles 21 of the vibrating device 19, while said bracket has spaced projecting arms at the other end thereof forming bearings for the vibrating device 18. The bracket 13 is formed with a depending'lug 23, while the vibrating device is formed with a depending lug 24. The depending lug 23 has an opening 25 therein and also a groove 26. A

spring 27 is formed with outwardly turned ends 28, and these ends are adapted to engage respectively the apertures 25 in the depending lugs 23 and 24, while the shank of the spring engages the groove 26. The spring operates normally to hold the vibrating device in raised position, and with its projection out of engagement with the serrations in the rotatable disk 5.

It is understood, of course, that the manner of supporting and the spring construction is the same for both vibrating devices. Each vibrating device is also provided with an upwardly projecting post 27, which extends upwardly through an aperture 28 in the upper member 6 and has a central recess adapted to receive the needle of the reproducer 3.

It will be noted-that the vibrating device is plvoted, and, therefore, the upper end of the post will not only move up and down but will also move sidewise or back and forth in a transverse direction. The needle of the certain sound producer moves vertically in some machines, while in others it moves transversely. The post having the combined movements above noted will, therefore, vibrate the sound-producing diaphragm of either instrument.

It is understood that the phonograph table in some devices is designed to travel at the rate of 78 revolutions per minute, while in others it is designed to travel at 80 revolutions per minute. The speed-determining device above described is, therefore, provided with a set or row of serrations to be used when it is desired to obtain a speed of 7 8 revolutions per minute and another set or row of serrations which are to be used when it is desired to obtain a speed of 80 revolutions per minute. These serrations are mathematically determined. Let us assume, for example, that the key note or tone of the pltch pipe or tuning fork to be used is m A-key, producing 435 vibrations per inane second. If 78 revolutions per minute are desired, this means 1.3 revolutions per second. By dividing the number of vibrations of the key tone, that is, 435, by 1.3 I obtain substantially 335, and, therefore, the rotatable member is provided with 335 teeth or serrations.

It will be understood that when the phonograph table is rotating at 78 revolutions per minute, if there are 335 teeth then the vibrating member will produce in the sound reproducer, 435 vibrations per second or the A-tone. By comparing the tone produced by the vibrating member with a pitchpipe or tuning-fork and adjusting the regulator of the machine until these tones are the same, I am able to bring the rotating table to a predetermined speed of 78 revolutions per minute.

While I have described my device in detail as used for the purpose of obtaining a pro: determined speed in a phonograph table, it will be understood that it may be used for determining the speed of any driven member, and may be modified as may be necessary to obtain this effect, the essential features consisting in the rotating member with the mathematically determined number of serrations or teeth thereon adapted to,

produce a tone through actuating the vibrating member and comparing of this tone with the standard key note.

The lower disk or revolving member ispreferably made of bakelite and molded in this disk is a sleeve 29 which projects upwardly from the disk and which extends within the sleeve of the hand piece 9. A screw 30 extending through an aperture in the upper end of the sleeve 29 and into the hand piece secures the parts together, but permits the free rotation of the disk 5 relative to the member 6.

It is obvious that minor changes in the details of construction maybe made without departing from the spirit of the invention, as set forth in the appended claims.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is

1. A device for obtaining a predetermined speed in a driven member including in combination, a rotatable disk having serrations formed thereon concentric with the axis of rotation of said disk, a stationary member having an opening centrally therethrough, a hand piece having a sleeve extending through said opening and means for clamping the hand piece to said stationary member, a vibrating device carried by said stationary member and adapted to be brought into engagement with said serrations, means for normally holding said vibrating member 2. A device for obtaining predetermined speeds in a driven member including in combmation, a rotatable disk having two rows of serrations thereon corresponding respectively to the predetermined speeds desired, each of said rows of serrations being concentric with the center of rotation of said disk, astationary member, a hand piece for holding said stationary member from turning, means for securing thestationary member 0n the rotatable disk, a vibrating device associated with each row of serrations and a common bracket attached to said stationary member for supporting said vibrating devices,

3. A device for obtaining predetermined speeds in adriven member including in combmation, a rotatable disk having two rows of serrations thereon corresponding respectively to the predetermined speeds desired, each of said rows of serrations being concentric with the center of rotation of said disk, a stationary member, a handpiece' for holding said stationary member from tum ing, means for securing the stationary member on the rotatable disk, a vibrating device associated with each row of serrations, a' common bracket attached to said stationary member for supporting. said vibrating devices, a spring for holding each vibrating device normally out of contact with the serrations and means carried by the vibrating devices whereby the same may be caused to produce a sound.

-WELLI WARREN DEX. 

